Whitworth's method of scraping (mentioned in this article) is explained in this 1858 paper: https://en.wikisource.org/wiki/Miscellaneous_Papers_on_Mechanical_S

Whitworth's method of scraping (mentioned in this article) is explained in this 1858 paper: https://en.wikisource.org/wiki/Miscellaneous_Papers_on_Mechanical_Subjects/A_Paper_on_Plane_Metallic_Surfaces_or_True_Planes https://en.wikisource.org/wiki/Miscellaneous_Papers_on_Mecha...